In 113 patients with idiopathic cardiomyopathy paired sera obtained 2-4 weeks apart were examined for neutralizing antibody to coxsackie B 1-6, and echo 4, 6, 7, 9 and 11 viruses. Only eight cases (6.9 per cent) showed a significant change in titer, indicating a virus infection during or shortly before the study. Complement-fixing antibody titers were measured in 126 patients and neutralizing antibodies in 116 patients with idiopathic cardiomyopathy. More patients had complement-fixing antibody titers &ges; 1 : 4 to coxsackie B and herpes simplex virus than did controls (p > 0.05). Neutralizing antibody titers to coxsackie B 1 and B 3 virus were also higher in patients (p > 0.01 for titers &ges; 1 : 4 and p > 0.05 for titers &ges; l : 16). Complement-fixing antibody titers &ges; 1 : 4 to herpes simplex virus were more frequent (p > 0.05) in hypertrophic cardiomyopathy and those to coxsackie B, herpes simplex and influenza A virus were more frequent in congestive cardiomyopathy. Neutralizing antibody titers were more common to coxsackie B 3 (p < 0.05 for titers of &ges; 1 : 4) in hypertrophic cardiomyopathy, while in congestive cardiomyopathy they were more common to coxsackie B 1 (p < 0.01 for titers &ges; 1 : 4 and p < 0.05 for titers &ges; 1 : 16), to coxsackie B 3 virus (p < 0.001 for titers &ges; 1 :4 and p < 0.05 for titers &ges; 1 : 16) and to coxsackie B 5 (p < 0.05 for titers >1 1 : 4 or more) and to echo 6 virus (p < 0.05 for titers &ges; 1 : 4 and &ges; 1 : 128). Immunofluorescent study of 61 cases showed no virus antigens in the biopsied myocardium even in patients who had significant changes in neutralizing antibody titers in paired sera. These results suggest a relationship between virus infection and idiopathic cardiomyopathy not only of the congestive type but also of the hypertrophic type. However, they do not provide definite proof of the virus infection theory of the disease.

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The present study was undertaken in an attempt to clarify whether or not any relationship exists between the echocardiographic indices of cardiac function and the severity of progressive muscular dystrophy of the Duchenne type (PMD). A total of 75 patients with PMD was used for analysis. Among the echocardiographic parameters measured in the study, the maximal diastolic endocardial velocity (DEVM) and ejection fraction (EF) revealed a gradual decreasing tendency with increasing severity of the disorder. It can be concluded therefore that DEVM and EF may represent useful indices in the assessment of cardiac function in PMD.

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We studied the regulatory mechanism of blood pressure in uremic patients (UP) treated with long-term hemodialysis. The cardiac index (CI) was higher in UP than in normal control(NC). Total peripheral resistance (TPR) in hypertensive (U-Hyper) and normotensive (U-Normo) uremic patients was almost the same as that in NC but TPR in hypotensive uremic patients (U-Hypo) was lower than in NC. High CI in U-Hyper and low TPR in U-Hypo seem to be the causes of their blood pressure abnormalities. All patients had severe anemia. There was a significant positive correlation between hematocrit (Ht) and TPR in UP as well as in NC. The regression line of correlation between Ht (x axis) and TPR (y axis) in UP was shifted to the left from that of NC, suggesting TPR was higher even in U-Hypo than in NC. There was a significant negative correlation between Ht and CI in UP as well as in NC. The regression line of correlation between Ht (x axis) and CI (y axis) in UP was shifted to the left from that in NC, suggesting that CI was lower even in U-Hyper than that in NC. Therefore, higher TPR relative to Ht in U-Hyper and lower CI relative to Ht in U-Hypo may actually be principal causes of their blood pressure abnormalities. Circulating plasma volume and extracellular fiuid volume were significantly higher in UP even after hemodialysis but there was no significant difference among subgroups of uremia. Plasma renin activity (PRA) was higher in UP than in NC. However, PRA in U-Hypo was significantly lower than that in U-Hyper or U-Normo. PRA in UP, even in U-Hypo, was inappropriately high relative to sodium/volume status. There was a significant positive correlation between TPR and PRA in UP. Therefore, higher TPR in UP relative to Ht than NC might be a result of elevated PRA. The level of blood pressure in UP seems to be regulated mainly by renin-angiotensin system. All patients were dialysed under the same condition. Heart rate and TPR increased after dialysis in U-Hyper and U-Hypo. However, no change occurred in these parameters throughout dialysis in U-Hypo. The responsiveness of renin secretion upon dialysis was lower in U-Hypo than in other two groups. Therefore, autonomic dysfunction may partly contribute to the development and maintenance of chronic hypotension in U-Hypo.

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Profound hypothermia with core cooling has been considered unsafe as compared with surface cooling because of the induced metabolic acidosis. We carried out studies on mongrel dogs to determine whether or not conventional cardiopulmonary bypass with pulsatile blood flow for core cooling could replace the bypass with non-pulsatile flow. The recovery time from anoxic damage of the brain due to circulatory arrest was also studied. Cerebral excess lactate (ΔXL) (Huckabee) was determined throughout the course of hypothermia. During the cooling period from 30°C down to 20°C, the mean value of ΔXL in the pulsatile group was significantly lower than that in the non-pulsatile group (p < 0.01). After forty minutes of the first total arrest at 20°C, thirty minutes of pulsatile perfusion tended to eliminate the anaerobic metabolism of the brain caused by the first total circulatory arrest (p < 0.1). Thus, the anaerobic metabolism in the brain appears to be highly suppressed with pulsatile cardiopulmonary bypass during the cooling period. Correction of congenital heart disease in infancy can probably be more safely performed if pulsatile cardiopulmonary bypass for cooling and rewarming is employed instead of the non-pulsatile bypass.

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Three cases with Eisenmenger syndrome were reported. Two of them were infants and one was adolescent. In the infant cases, the left atrial volume was small and the left atrial volume change ratio was large. In the adolescent case, the left atrial volume was large and the left atrial volume change ratio was reduced. In the adolescent case, the decrease in the left atrial volume change ratio probably caused the pulmonary hypertension, but in the infant cases, the left atrial volume change ratio was not decreased and therefore this cannot be the cause of the pulmonary hypertension. The brain damage with microcephaly might play a role in the development of the high pulmonary vascular resistance.

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A rare and instructive case of cardiac involvement by reticulum cell sarcoma in a 72-year-old woman was presented. In this case acute myocardial infarction was suspected on an electrocardiogram but was proved absent, and only scattered tumor infiltration was demonstrated at autopsy.

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An experimental study was performed on the potential distribution surrounding the heart. The dog heart was isolated, perfused with Tyrode solution and was placed in a spherical container filled with the same solution. The potential measurement was made at 156 sites on the epicardial surface as well as at the same number of locations on the corresponding surface in the solution 0.5 to 2.0 cm apart from the epicardium. The results indicated that considerable simplification of isopotential lines occurred already at a distance of 2 cm from the heart. With the electrode array on the spherical surface enclosing the heart, similar maps were constructed and an index to express the complexity of the map was calculated. With artificial extrasystoles arising from an epicardial site, the potential on the epicardium showed a main negative area with very closely located positive areas. The basis and methods for the determination of epicardial potential from the surface measurements were critically discussed.

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Spatial electrocardiography can express the spatial characteristics of electromotive forces of the heart quantiatively. The pattern of the sequential changes of these spatial characteristics of the cardiac vectors also provides important diagnostic informations. Accordingly, spatial electrocardiography is considered to be useful in cinical cardiology in association with conventional electrocardiography and vectorcardiography.

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Some selected topics and future prospects in electrocardiography were stated, namely, electrocardiograph, computer interpretation of electrocardiogram, body surface mapping and electrocardiography at large. Special attention was paid to computer application to signal processing and decision making with respect to electrocardiography. A brief review for inverse problem in electrocardiography was made as well. In regard to body surface mapping, another way of expression of the maps was proposed where, instead of routine isopotential map, isochrone map for ventricular activation time of QRS complexes was used for representing the ventricular electrophysiologic activities.

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Recordings of His bundle electrogram combined with stimulation method are very useful to diagnose the locations of conduction disturbance, to understand the mechanisms of arrhythmias and to evaluate the electrophysiologic properties of the A-V conducting system. However, there remain some unsolved problems regarding the electrophysiologic interpretations and prognostic implications based on His bundle electrograms. In this panel discussion, some aspects with regard to the usefulness and limitations of His bundle electrogram will be discussed from our data obtained in 300 patients.

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Intracardiac stimulation (IS) has been widely used as the diagnostic method for various kinds of arrhythmias. Our results as to IS are as follows: 1) Since sinus recovery time (SNRT) closely correlated with basic cycle length (BCL) in 71 normal cases (r = 0.82, p < 0.001), upper range of SNRT in normal was expressed as SNRT = 1.4BCL + 451 msec. 2) Paroxysmal supraventricular tachycardia (PSVT) induced by IS was fairly similar to the spontaneous PSVT (l07 cases). Therefore, IS can be used to confirm the diagnosis of PSVT and also to evaluate the effectiveness of antiarrhythmic agents on PSVT. 3) Although induction or termination of ventricular tachycardia by IS may be useful in a general sense, dangerous tachyarrhythmias were sometimes provoked, indicating this test should be carried out under the utmost care.

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Twenty-four-hour recordings of electrocardiogram (ECG) were obtained from 1528 subjects. Sick sinus syndrome (SSS) was observed in 34 and advanced or complete AV block (CAVB) in 13 subjects. During the period studied 21 patients had died, who showed complicated ventricular premature contractions in 9 (multiform 6, short run 2, repetitive 1). Seventy-three patients with artificial cardiac pacing who were admitted at three different institutions were analyzed. The discrepancy of degree of block was observed between His bundle electrocardiographic findings and 24-hour ECG recordings. In 15 patients there was no correlation between sinus node recovery time following overdrive suppression and pauses following the termination of tachycardia (r = -0.0896, N. S.). In 49 normal subjects 24-hour heart rate ranged from a high of 170 to a low of 36 beats/min. Longest R-R interval ranged from 2.08 to 0.86 sec (mean 1.25 i 0.22 sec). The critical level of longest R-R interval to differentiate between normal group and groups with SSS or CAVB was about 1.6 sec. Above results suggest that Holter monitoring permits a precise diagnosis of arrhythmias and that both HBE and Holter monitoring should be used for the determination of pacemaker implantation especially in those with syncope or dizziness but without evidence of marked bradycardia .

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The clinical meaning of precordial ST segment mapping for assessment of infarct size was studied in 12 patients with acute anterior myocardial infarction. ΣST₃₉ (the sum of ST segment elevations in 39 precordial leads), ΣSTv_l-6 (the sum of ST segment elevations in the standard chest leads) and ST_MAX (the maximum of ST segment elevation in 39 precordial leads) were obtained serially after the onset from precordial electrocardiographic mapping records. The infarct size and the time (Tf) when the evolution of myocardial infarction finished were calculated by the total creatine phosphokinase released (ΣCPK) and serial changes in CPK releasing rate, respectively. ΣSTv_l-6 at Tf, as closely as ΣST₃₉ (r = 0.82, p < 0.01), correlated with ΣCPK (r = 0.79, p < 0.01). Even ST_MAX at the time of Tf significantly correlated with ΣCPK (r = 0.60, p < 0.05), although the correlation coefficient was not so well as the former two. These results showed that ΣSTv_l-6 reflected infarct size as satisfactorily as ΣST₃₉ and could be useful for measuring infarct size.

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The present status of exercise testing in coronary artery disease (CAD) was discussed in respect to test protocols, ECG criteria and lead systems, and hemodynamic responses. Advantages of modern multistage protocols over single-stage ones such as Master two-step tests are obvious in diagnostic accuracy and patient's safety. Clinical significance of horizontal and downsloping ST depression has already been established. Diagnostic significance of other exercise-induced ECG alterations such as slow upsloping ST depression, ST elevation, U-wave inversion, and R-wave amplitude changes was discussed. The latter parameter is still controversial as to its clinical significance. Use of an inadequate ECG lead system is one of major causes of false negative tests. Necessity of multiple lead systems was emphasized for higher diagnostic accuracy. From the view point of cost-efficacy relation, we will recommend simultaneous recording of CC5 or CM5, V3 and CL or III in routine exercise testing for screening of CAD. Test results such as exercise time, and heart rate and systolic blood pressure responses are also useful parameters for the evaluation of the severity and prognosis of CAD. It was emphasized that inexercise monitoring of ECG and blood pressure is indispensible in multistage exercise testing for improvement of diagnostic accuracy as well as patient's safety.

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